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Er 32 collet issue
- Thread starter stirboy01
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Thanks for the picture. It helps to understand how you are measuring.
I'd recommend you make the stem of the tool perpendicular (square) to the spindle axis. [Plunger rod is at the max diameter of rod and square to the workpiece.] I realize you you are trying to measure in close, but having an angle can introduce errors. Can't tell from the picture if the indicator tip is touching the collet or not. The tip should only touch the workpiece.
A tip that I have to share is to try pushing in the indicator further, say by another 0.010 to 0.030". (Position dial indicator so the initial measurement is at 0.010", as an example.) The measured relative variation from minus to plus should be the same. Sometimes the indicator can stick or do something funky at certain positions. The runout (positive measurement - negative measurement) for the second measurement should be identical to what you measured previously. If not, something isn't right. If the collet is tight, the runout should be independent of the initial plunger (dial indicator) setting.
I'd recommend you make the stem of the tool perpendicular (square) to the spindle axis. [Plunger rod is at the max diameter of rod and square to the workpiece.] I realize you you are trying to measure in close, but having an angle can introduce errors. Can't tell from the picture if the indicator tip is touching the collet or not. The tip should only touch the workpiece.
A tip that I have to share is to try pushing in the indicator further, say by another 0.010 to 0.030". (Position dial indicator so the initial measurement is at 0.010", as an example.) The measured relative variation from minus to plus should be the same. Sometimes the indicator can stick or do something funky at certain positions. The runout (positive measurement - negative measurement) for the second measurement should be identical to what you measured previously. If not, something isn't right. If the collet is tight, the runout should be independent of the initial plunger (dial indicator) setting.
i have ordered and returned two other 1/4 collets which have resulted with approximately the same readings as the collet i got with the kit.. this hints to me that im experiencing a common problem coming from the collet itself.. ordered a dowel today and will check when it arrives.. thanks bill
received new ss 1/4 " dowel other day .. checked it in the collet this am and the best reading i could get was a negative .002 give or take a couple tenths. after clocking the collet around to 3/6/9 and back to 12 the worst ro i had was close to - 0.005.. i got similar results when i was using a quarter inch center drill so i believe the drill bit to be as straight as the new dowel.. im still thinking a little work on the threads of the holder is not going to hurt anything..
well i finally took a few passes on the threads of the holder and it didnt hurt anything or help much either.. not much help as about the best reading i can get out of the 1/4 collet is around .002 .. only way i can think of to check the trueness of the od of the collet is to turn a piece of stock to a snug fit on the collet and slide it on and indicate the od to see if it is out of round with the bore..
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The threads of the holder should have nothing to do with the trueness of the ID of the collet. It's the runout of the ID of the collet that one is concerned with. (We are assuming the collet chuck is true, and the collet is correctly made.) Is the collet clean? If there is swarf (little chips or metal slivers) in the collet, it could affect runout. You could clean it out with some thin cardboard, like from a cracker box, or a sheet of paper. If you have compressed air, you could blow it out (being careful not to get junk in your eyes).
What does the bottom of your indicator plunger look like? Is it smooth, or does it have some faceting? My old Federal C21 had some slight faceting due to wear and being over 60 years old, sometimes it would oddly indicate. New indicator tips are inexpensive to source, or you could make your own. The thread should be 4-48. When you measured the runout was there any oil on the workpiece? Some people say not to use oil, others do. I find a very thin coat of light machine oil reduces tip stiction.
However, can we revisit what you are trying to accomplish again? If I recall correctly it has to do with valves. If you are facing the part of the valves that face the engine, not the ground edges that seal to the head, then you shouldn't care if there is 0.002 runout or 0.004. It won't matter. If you are trying to correct the ground part of the valve, then I wouldn't use the lathe at all. That one typically "grinds to fit" the head using valve grinding compound. What is the "end task" that you are trying to do?
What does the bottom of your indicator plunger look like? Is it smooth, or does it have some faceting? My old Federal C21 had some slight faceting due to wear and being over 60 years old, sometimes it would oddly indicate. New indicator tips are inexpensive to source, or you could make your own. The thread should be 4-48. When you measured the runout was there any oil on the workpiece? Some people say not to use oil, others do. I find a very thin coat of light machine oil reduces tip stiction.
However, can we revisit what you are trying to accomplish again? If I recall correctly it has to do with valves. If you are facing the part of the valves that face the engine, not the ground edges that seal to the head, then you shouldn't care if there is 0.002 runout or 0.004. It won't matter. If you are trying to correct the ground part of the valve, then I wouldn't use the lathe at all. That one typically "grinds to fit" the head using valve grinding compound. What is the "end task" that you are trying to do?
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I made an eBay purchase of an R8 to ER32 collet set for my mill. For $50 for the adapter and 11 collets, I thought how bad could it be? It’s from India, but when it arrived, I was initially impressed with the appearance and apparent quality. But checking the runout, it was severe, in the 0.009 to 0.010 range, measured with a 3/8” dowel pin. I compared with a 3/8” R8 collet and the same pin and found the runout was less than 0.001. Poking around, the issue was with the adapter, and the manufacturer readily agreed to replace it. I will report upon its arrival.
Two attached videos show the ”native” runout with the R8 collet, and the runout on the ER32 adapter.
Two attached videos show the ”native” runout with the R8 collet, and the runout on the ER32 adapter.
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Cool videos. Could be the collet is bad, as Winegrower says. Or the spindle & collet chuck if for some reason there's an issue with the measurement technique. Not saying there's an issue, but the overall TIR could be due to multiple causes. Are there any burrs or dings on the collet chuck, or register?
@stirboy01, I think your last post states that the TIR is 0.002? That's -0.001 to +0.001, or -0.002 to 0.000, etc. Or do you mean -0.002 to +0.002, which is a total of 0.004"? But what is the application again? What are you trying to do exactly? There might be an alternate way to do what you need to do, but it's hard for us to suggest an alternate approach if the task is unknown to us.
@stirboy01, I think your last post states that the TIR is 0.002? That's -0.001 to +0.001, or -0.002 to 0.000, etc. Or do you mean -0.002 to +0.002, which is a total of 0.004"? But what is the application again? What are you trying to do exactly? There might be an alternate way to do what you need to do, but it's hard for us to suggest an alternate approach if the task is unknown to us.
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It was not the collet. The bad runout was exactly the same with several collets of different diameter, and exactly the same on the outside of the R8 to ER32 adapter. Pretty easy to see where the problem was. A new adapter has been shipped.